A024277 E.g.f.: log(1+tanh(x)*tan(x))/2 (even powers only).

0, 1, -6, 176, -8176, 691456, -86186496, 15358324736, -3667315849216, 1135407181398016, -441731548179726336, 211079248633366839296, -121507103129359646457856, 82940335057202543199256576

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Example

log(1+tanh(x)*tan(x))/2 = 1/2*x^2 - 1/4*x^4 + 11/45*x^6 - 73/360*x^8 +- ... .

Mathematica

Log[ 1+Tanh[ x ]*Tan[ x ]]/2 (* Even Part *)

Crossrefs

Cf. A009398.

Cf. A101921.

Sequence in context: A318538 A071095 A134632 * A012177 A012227 A012152

Adjacent sequences: A024274 A024275 A024276 * A024278 A024279 A024280

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs Mar 1997

Status

approved